I just cant figure this out, I need help. I want to make either a full rod or a handle to go on existing rods with a spring that rates at 35 pounds, so you can consistantly ram the ball everytime, I know some one had them for sale before but I never seen one. Any one have an idea how the inside of this would work ?, or look. Should the spring set off a click to let you know when, or maybe a button that pops up at 35 pounds or what ?, I have the machines to make them if I can just figure it out.